The hepatitis C virus (HCV) is the leading cause of chronic liver disease worldwide. (Boyer, N. et al., J. Hepatol. 32:98-112, 2000). HCV causes a slow growing viral infection and is the major cause of cirrhosis and hepatocellular carcinoma (Di Besceglie, A. M. and Bacon, B. R., Scientific American, October: 80-85, 1999; Boyer, N. et al., J. Hepatol. 32:98-112, 2000). It is estimated there are about 130-150 million people with chronic hepatitis C virus infection. Hepatitis C-related liver diseases cause approximately 350,000 to 500,000 deaths each year. HCV infection becomes chronic in about 55-85% of cases, with many patients initially being asymptomatic. About 15-30% of patients with chronic hepatitis due to HCV develop cirrhosis within about 20 years. (Hepatitis C Fact Sheet, World Health Organization Fact Sheet No. 164, April 2014). Development of cirrhosis due to HCV also increases the risk of hepatocellular cancer (The Merck Manual Online, Chronic Hepatitis, last revision February 2014).
In light of the fact that HCV infection has reached epidemic levels worldwide, and has tragic effects on the infected patient, there remains a strong need to provide new effective pharmaceutical agents to treat hepatitis C that have low toxicity to the host. Further, given the rising threat of other flaviviridae infections, there remains a strong need to provide new effective pharmaceutical agents that have low toxicity to the host. Therefore, there is a continuing need for effective treatments of flavivirus infections and HCV infections.